Technical Reference Manual
002-29852 Rev. *B
Bits Name
SW
HW
Default or
Enum
Description
3
C_MASKINTS
RW
R
X
When debug is enabled, the debugger can write to this
bit to mask PendSV, SysTick and external configurable
interrupts. The effect of any attempt to change the
value of this bit is UNPREDICTABLE unless both:
- before the write to DHCSR, the value of the C_HALT
bit is 1
- the write to the DHCSR that changes the
C_MASKINTS bit also writes 1 to the C_HALT bit
This means that a single write to DHCSR cannot set
the C_HALT to 0 and change the value of the
C_MASKINTS bit. The bit does not affect NMI. When
DHCSR.C_DEBUGEN is set to 0, the
value of this bit is UNKNOWN. For more information
about the use of this bit see Table C1-7 on Arm TRM
page C1-326.
16
S_REGRDY
R
RW
X
A handshake flag for transfers through the DCRDR:
- Writing to DCRSR clears the bit to 0.
- Completion of the DCRDR transfer then sets the bit
to 1.
For more information about DCRDR transfers see
Debug Core Register Data Register, DCRDR on Arm
TRM page C1-337.
0: There has been a write to the DCRDR, but the
transfer is
not complete.
1: The transfer to or from the DCRDR is complete.
This bit is only valid when the processor is in Debug
state, otherwise the bit is UNKNOWN.
17
S_HALT
R
RW
0
Indicates whether the processor is in Debug state.
18
S_SLEEP
R
RW
0
Indicates whether the processor is sleeping. The
debugger must set the DHCSR.C_HALT bit to 1 to
gain control, or
wait for an interrupt or other wakeup event to wakeup
the system.
19
S_LOCKUP
R
RW
0
Indicates whether the processor is locked up because
of an unrecoverable exception. See Unrecoverable
exception cases on Arm TRM page B1-238 for more
information. This bit can only read as 1 when accessed
by a remote debugger using the
DAP. The bit clears to 0 when the processor enters
Debug state.
20:23 DBG_KEY_P1
W
R
X
Debug key:
Software must write 0xA05F to [31:16] to enable write
accesses to bits
[15:0], otherwise the processor ignores the write
access.
24
S_RETIRE_ST
R
RW
X
When not in Debug state, indicates whether the
processor has completed execution of at least one
instruction since the last read of DHCSR. This is a
sticky bit, that clears to 0 on a read of DHCSR.
This bit is UNKNOWN:
- after a Local reset, but is set to 1 as soon as the
processor completes execution of an instruction
- when S_LOCKUP is set to 1
- when S_HALT is set to 1.
When the processor is not in Debug state, a debugger
can check this bit to determine if the processor is
stalled on a load, store or fetch access.
25
S_RESET_ST
R
RW
1
Indicates whether the processor has been reset since
the last read of DHCSR. This is a sticky bit, that clears
to 0 on a read of DHCSR
26:31 DBG_KEY_P2
W
R
X
See description for Bit 20
187
2022-04-18
TRAVEO™ T2G Automotive MCU: TVII-B-E-4M body controller entry registers